mahara-contributors team mailing list archive

[Mahara Bot <891170@xxxxxxxxxxxxxxxxxx>]

Reviewed:  https://reviews.mahara.org/881
Committed: http://gitorious.org/mahara/mahara/commit/93639aacf1423a9eabdaf06216912160a8f07494
Submitter: Andrew Robert Nicols (andrew.nicols@xxxxxxxxxxx)
Branch:    master

commit 93639aacf1423a9eabdaf06216912160a8f07494
Author: Richard Mansfield <richard.mansfield@xxxxxxxxxxxxxxx>
Date:   Thu Nov 24 16:41:59 2011 +1300

    Fix race condition in cron (bug #891170)
    
    When cron finds a function with a stale (day-old) lock, just remove
    the lock and give up rather than trying to execute the function again.
    It's already pretty late, and waiting another minute for the next cron
    to start won't make a difference.
    
    This should avoid the case where two copies of cron both find the stale
    lock at the same time, and restart simultaneously.  It won't matter if
    cron_lock fails to get a $started value because the row has been
    deleted: the next instance of cron to run will be able to insert the
    row.
    
    Change-Id: I025aaf89d64f47466f1ba4c5bb8178317277ec2c
    Signed-off-by: Richard Mansfield <richard.mansfield@xxxxxxxxxxxxxxx>

-- 
You received this bug notification because you are a member of Mahara
Contributors, which is subscribed to Mahara.
https://bugs.launchpad.net/bugs/891170

Title:
  race conditions in cron

Status in Mahara ePortfolio:
  Fix Committed

Bug description:
  Thanks to tim hunt at the OU for pointing the first issue out:

  It's possible for cron_lock to fail to get the $started value if the row has been deleted between attempting to insert the record, and attempting to retrieve the start date
  http://gitorious.org/mahara/mahara/blobs/master/htdocs/lib/cron.php#line488

  Additionally, when we try to restart a job which has been running for > 24 hours, we should probably call cron_lock() rather than insert_record()
  http://gitorious.org/mahara/mahara/blobs/master/htdocs/lib/cron.php#line498

  That said, we're very unlikely to ever hit this given the use of cron.

To manage notifications about this bug go to:
https://bugs.launchpad.net/mahara/+bug/891170/+subscriptions